PHP's is_callable in TypeScript

How to use

Install via yarn add locutus and import: import { is_callable } from 'locutus/php/var/is_callable'.

Or with CommonJS: const { is_callable } = require('locutus/php/var/is_callable')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	is_callable('is_callable')	true
2	is_callable('bogusFunction', true)	true // gives true because does not do strict checking
3	function SomeClass () {} SomeClass.prototype.someMethod = function (){} var testObj = new SomeClass() is_callable([testObj, 'someMethod'], true, 'myVar') var $result = myVar	'SomeClass::someMethod'
4	is_callable(function () {})	true
5	is_callable(class MyClass {})	false

Notes

• The variable callableName cannot work as a string variable passed by reference as in PHP (since JavaScript does not support passing strings by reference), but instead will take the name of a global variable and set that instead. When used on an object, depends on a constructor property being kept on the object prototype

• Depending on the callableName that is passed, this function can use eval. The eval input is however checked to only allow valid function names, So it should not be unsafer than uses without eval (seeing as you can) already pass any function to be executed here.

Dependencies

This function uses the following Locutus functions:

• _phpRuntimeState (php/_helpers)
• _phpTypes (php/_helpers)

Here's what our current TypeScript equivalent to PHP's is_callable looks like.

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

import { getPhpGlobalScope, getPhpObjectEntry, setPhpGlobalEntry } from '../_helpers/_phpRuntimeState.ts'
import { type PhpRuntimeValue, toPhpArrayObject } from '../_helpers/_phpTypes.ts'

type CallableValue = PhpRuntimeValue

export function is_callable(mixedVar: CallableValue, syntaxOnly?: boolean, callableName?: string): boolean {
  //  discuss at: https://locutus.io/php/is_callable/
  // original by: Brett Zamir (https://brett-zamir.me)
  //    input by: François
  // improved by: Brett Zamir (https://brett-zamir.me)
  // improved by: KnightYoshi
  // improved by: Waldo Malqui Silva (https://fayr.us/waldo/)
  //      note 1: The variable callableName cannot work as a string variable passed by
  //      note 1: reference as in PHP (since JavaScript does not support passing
  //      note 1: strings by reference), but instead will take the name of
  //      note 1: a global variable and set that instead.
  //      note 1: When used on an object, depends on a constructor property
  //      note 1: being kept on the object prototype
  //      note 2: Depending on the `callableName` that is passed, this function can use eval.
  //      note 2: The eval input is however checked to only allow valid function names,
  //      note 2: So it should not be unsafer than uses without eval (seeing as you can)
  //      note 2: already pass any function to be executed here.
  //   example 1: is_callable('is_callable')
  //   returns 1: true
  //   example 2: is_callable('bogusFunction', true)
  //   returns 2: true // gives true because does not do strict checking
  //   example 3: function SomeClass () {}
  //   example 3: SomeClass.prototype.someMethod = function (){}
  //   example 3: var testObj = new SomeClass()
  //   example 3: is_callable([testObj, 'someMethod'], true, 'myVar')
  //   example 3: var $result = myVar
  //   returns 3: 'SomeClass::someMethod'
  //   example 4: is_callable(function () {})
  //   returns 4: true
  //   example 5: is_callable(class MyClass {})
  //   returns 5: false

  const validJSFunctionNamePattern = /^[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*$/

  let name = ''
  let obj: object | null = null
  let method = ''
  let validFunctionName = false

  const getFuncName = function (fn: { toString: () => string }): string {
    const funcNameMatch = /\W*function\s+([\w$]+)\s*\(/.exec(String(fn))
    if (!funcNameMatch) {
      return '(Anonymous)'
    }
    return funcNameMatch[1] ?? '(Anonymous)'
  }

  if (mixedVar == null) {
    return false
  }

  if (/(^class|\(this,)/.test(String(mixedVar))) {
    return false
  }

  if (typeof mixedVar === 'string') {
    obj = getPhpGlobalScope()
    method = mixedVar
    name = mixedVar
    validFunctionName = !!name.match(validJSFunctionNamePattern)
  } else if (typeof mixedVar === 'function') {
    return true
  } else if (
    Array.isArray(mixedVar) &&
    mixedVar.length === 2 &&
    mixedVar[0] !== null &&
    typeof mixedVar[0] === 'object' &&
    typeof mixedVar[1] === 'string'
  ) {
    const receiver = toPhpArrayObject(mixedVar[0])
    obj = receiver
    method = mixedVar[1]
    name =
      (typeof receiver.constructor === 'function' ? getFuncName(receiver.constructor) : '(Anonymous)') + '::' + method
  }

  const callableCandidate = obj ? getPhpObjectEntry(obj, method) : undefined
  if (syntaxOnly || typeof callableCandidate === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  // validFunctionName avoids exploits
  // biome-ignore lint/security/noGlobalEval: needed for PHP port
  if (validFunctionName && typeof eval(method) === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  return false
}

import { getPhpGlobalScope, getPhpObjectEntry, setPhpGlobalEntry } from '../_helpers/_phpRuntimeState.ts'
import { toPhpArrayObject } from '../_helpers/_phpTypes.ts'

export function is_callable(mixedVar, syntaxOnly, callableName) {
  //  discuss at: https://locutus.io/php/is_callable/
  // original by: Brett Zamir (https://brett-zamir.me)
  //    input by: François
  // improved by: Brett Zamir (https://brett-zamir.me)
  // improved by: KnightYoshi
  // improved by: Waldo Malqui Silva (https://fayr.us/waldo/)
  //      note 1: The variable callableName cannot work as a string variable passed by
  //      note 1: reference as in PHP (since JavaScript does not support passing
  //      note 1: strings by reference), but instead will take the name of
  //      note 1: a global variable and set that instead.
  //      note 1: When used on an object, depends on a constructor property
  //      note 1: being kept on the object prototype
  //      note 2: Depending on the `callableName` that is passed, this function can use eval.
  //      note 2: The eval input is however checked to only allow valid function names,
  //      note 2: So it should not be unsafer than uses without eval (seeing as you can)
  //      note 2: already pass any function to be executed here.
  //   example 1: is_callable('is_callable')
  //   returns 1: true
  //   example 2: is_callable('bogusFunction', true)
  //   returns 2: true // gives true because does not do strict checking
  //   example 3: function SomeClass () {}
  //   example 3: SomeClass.prototype.someMethod = function (){}
  //   example 3: var testObj = new SomeClass()
  //   example 3: is_callable([testObj, 'someMethod'], true, 'myVar')
  //   example 3: var $result = myVar
  //   returns 3: 'SomeClass::someMethod'
  //   example 4: is_callable(function () {})
  //   returns 4: true
  //   example 5: is_callable(class MyClass {})
  //   returns 5: false

  const validJSFunctionNamePattern = /^[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*$/

  let name = ''
  let obj = null
  let method = ''
  let validFunctionName = false

  const getFuncName = function (fn) {
    const funcNameMatch = /\W*function\s+([\w$]+)\s*\(/.exec(String(fn))
    if (!funcNameMatch) {
      return '(Anonymous)'
    }
    return funcNameMatch[1] ?? '(Anonymous)'
  }

  if (mixedVar == null) {
    return false
  }

  if (/(^class|\(this,)/.test(String(mixedVar))) {
    return false
  }

  if (typeof mixedVar === 'string') {
    obj = getPhpGlobalScope()
    method = mixedVar
    name = mixedVar
    validFunctionName = !!name.match(validJSFunctionNamePattern)
  } else if (typeof mixedVar === 'function') {
    return true
  } else if (
    Array.isArray(mixedVar) &&
    mixedVar.length === 2 &&
    mixedVar[0] !== null &&
    typeof mixedVar[0] === 'object' &&
    typeof mixedVar[1] === 'string'
  ) {
    const receiver = toPhpArrayObject(mixedVar[0])
    obj = receiver
    method = mixedVar[1]
    name =
      (typeof receiver.constructor === 'function' ? getFuncName(receiver.constructor) : '(Anonymous)') + '::' + method
  }

  const callableCandidate = obj ? getPhpObjectEntry(obj, method) : undefined
  if (syntaxOnly || typeof callableCandidate === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  // validFunctionName avoids exploits
  // biome-ignore lint/security/noGlobalEval: needed for PHP port
  if (validFunctionName && typeof eval(method) === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  return false
}

// php/_helpers/_phpTypes (Locutus helper dependency)
type PhpNullish = null | undefined

type PhpInput = {} | PhpNullish

type PhpScalar = string | number | boolean

type PhpPrimitive = PhpScalar | bigint

type PhpList<T = PhpInput> = T[]

type PhpAssoc<T = PhpInput> = { [key: string]: T }

type PhpArrayLike<T = PhpInput> = PhpList<T> | PhpAssoc<T>

type PhpFunctionValue = (...args: PhpInput[]) => PhpInput

interface PhpRuntimeAssoc {
  [key: string]: PhpRuntimeValue
}

interface PhpRuntimeList extends Array<PhpRuntimeValue> {}

type PhpRuntimeValue = PhpPrimitive | PhpNullish | PhpRuntimeList | PhpRuntimeAssoc | PhpFunctionValue

function isObjectLike(value: PhpInput): value is PhpArrayLike<PhpInput> {
  return typeof value === 'object' && value !== null
}

function isPhpArrayObject<T = PhpInput>(value: PhpInput): value is PhpAssoc<T> {
  return isObjectLike(value)
}

function toPhpArrayObject<T = PhpInput>(value: PhpInput): PhpAssoc<T> {
  if (isPhpArrayObject<T>(value)) {
    return value
  }

  return {}
}

// php/_helpers/_phpRuntimeState (Locutus helper dependency)
interface LocutusRuntimeContainer {
  php?: PhpAssoc<PhpInput>
}

type GlobalWithLocutus = {
  $locutus?: LocutusRuntimeContainer
  [key: string]: PhpInput
}

const globalContext: GlobalWithLocutus =
  typeof window === 'object' && window !== null ? window : typeof global === 'object' && global !== null ? global : {}

function setPhpGlobalEntry(key: string, value: PhpInput): void {
  globalContext[key] = value
}

function getPhpGlobalScope(): PhpAssoc<PhpInput> {
  return globalContext
}

function getPhpObjectEntry(value: PhpInput, key: string): PhpInput | undefined {
  if ((typeof value !== 'object' && typeof value !== 'function') || value === null) {
    return undefined
  }

  let current: object | null = value
  while (current) {
    const descriptor = Object.getOwnPropertyDescriptor(current, key)
    if (descriptor) {
      if (typeof descriptor.get === 'function') {
        const getterValue = descriptor.get.call(value)
        return typeof getterValue === 'undefined' ? undefined : getterValue
      }
      const directValue = descriptor.value
      return typeof directValue === 'undefined' ? undefined : directValue
    }
    current = Object.getPrototypeOf(current)
  }

  return undefined
}

// php/var/is_callable (target function module)
type CallableValue = PhpRuntimeValue

function is_callable(mixedVar: CallableValue, syntaxOnly?: boolean, callableName?: string): boolean {
  //  discuss at: https://locutus.io/php/is_callable/
  // original by: Brett Zamir (https://brett-zamir.me)
  //    input by: François
  // improved by: Brett Zamir (https://brett-zamir.me)
  // improved by: KnightYoshi
  // improved by: Waldo Malqui Silva (https://fayr.us/waldo/)
  //      note 1: The variable callableName cannot work as a string variable passed by
  //      note 1: reference as in PHP (since JavaScript does not support passing
  //      note 1: strings by reference), but instead will take the name of
  //      note 1: a global variable and set that instead.
  //      note 1: When used on an object, depends on a constructor property
  //      note 1: being kept on the object prototype
  //      note 2: Depending on the `callableName` that is passed, this function can use eval.
  //      note 2: The eval input is however checked to only allow valid function names,
  //      note 2: So it should not be unsafer than uses without eval (seeing as you can)
  //      note 2: already pass any function to be executed here.
  //   example 1: is_callable('is_callable')
  //   returns 1: true
  //   example 2: is_callable('bogusFunction', true)
  //   returns 2: true // gives true because does not do strict checking
  //   example 3: function SomeClass () {}
  //   example 3: SomeClass.prototype.someMethod = function (){}
  //   example 3: var testObj = new SomeClass()
  //   example 3: is_callable([testObj, 'someMethod'], true, 'myVar')
  //   example 3: var $result = myVar
  //   returns 3: 'SomeClass::someMethod'
  //   example 4: is_callable(function () {})
  //   returns 4: true
  //   example 5: is_callable(class MyClass {})
  //   returns 5: false

  const validJSFunctionNamePattern = /^[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*$/

  let name = ''
  let obj: object | null = null
  let method = ''
  let validFunctionName = false

  const getFuncName = function (fn: { toString: () => string }): string {
    const funcNameMatch = /\W*function\s+([\w$]+)\s*\(/.exec(String(fn))
    if (!funcNameMatch) {
      return '(Anonymous)'
    }
    return funcNameMatch[1] ?? '(Anonymous)'
  }

  if (mixedVar == null) {
    return false
  }

  if (/(^class|\(this,)/.test(String(mixedVar))) {
    return false
  }

  if (typeof mixedVar === 'string') {
    obj = getPhpGlobalScope()
    method = mixedVar
    name = mixedVar
    validFunctionName = !!name.match(validJSFunctionNamePattern)
  } else if (typeof mixedVar === 'function') {
    return true
  } else if (
    Array.isArray(mixedVar) &&
    mixedVar.length === 2 &&
    mixedVar[0] !== null &&
    typeof mixedVar[0] === 'object' &&
    typeof mixedVar[1] === 'string'
  ) {
    const receiver = toPhpArrayObject(mixedVar[0])
    obj = receiver
    method = mixedVar[1]
    name =
      (typeof receiver.constructor === 'function' ? getFuncName(receiver.constructor) : '(Anonymous)') + '::' + method
  }

  const callableCandidate = obj ? getPhpObjectEntry(obj, method) : undefined
  if (syntaxOnly || typeof callableCandidate === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  // validFunctionName avoids exploits
  // biome-ignore lint/security/noGlobalEval: needed for PHP port
  if (validFunctionName && typeof eval(method) === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  return false
}

// php/_helpers/_phpTypes (Locutus helper dependency)
function isPhpArrayObject(value) {
  return typeof value === 'object' && value !== null
}

function toPhpArrayObject(value) {
  if (isPhpArrayObject(value)) {
    return value
  }

  return {}
}

// php/_helpers/_phpRuntimeState (Locutus helper dependency)
const globalContext =
  typeof window === 'object' && window !== null ? window : typeof global === 'object' && global !== null ? global : {}

function setPhpGlobalEntry(key, value) {
  globalContext[key] = value
}

function getPhpGlobalScope() {
  return globalContext
}

function getPhpObjectEntry(value, key) {
  if ((typeof value !== 'object' && typeof value !== 'function') || value === null) {
    return undefined
  }

  let current = value
  while (current) {
    const descriptor = Object.getOwnPropertyDescriptor(current, key)
    if (descriptor) {
      if (typeof descriptor.get === 'function') {
        const getterValue = descriptor.get.call(value)
        return typeof getterValue === 'undefined' ? undefined : getterValue
      }
      const directValue = descriptor.value
      return typeof directValue === 'undefined' ? undefined : directValue
    }
    current = Object.getPrototypeOf(current)
  }

  return undefined
}

// php/var/is_callable (target function module)
function is_callable(mixedVar, syntaxOnly, callableName) {
  //  discuss at: https://locutus.io/php/is_callable/
  // original by: Brett Zamir (https://brett-zamir.me)
  //    input by: François
  // improved by: Brett Zamir (https://brett-zamir.me)
  // improved by: KnightYoshi
  // improved by: Waldo Malqui Silva (https://fayr.us/waldo/)
  //      note 1: The variable callableName cannot work as a string variable passed by
  //      note 1: reference as in PHP (since JavaScript does not support passing
  //      note 1: strings by reference), but instead will take the name of
  //      note 1: a global variable and set that instead.
  //      note 1: When used on an object, depends on a constructor property
  //      note 1: being kept on the object prototype
  //      note 2: Depending on the `callableName` that is passed, this function can use eval.
  //      note 2: The eval input is however checked to only allow valid function names,
  //      note 2: So it should not be unsafer than uses without eval (seeing as you can)
  //      note 2: already pass any function to be executed here.
  //   example 1: is_callable('is_callable')
  //   returns 1: true
  //   example 2: is_callable('bogusFunction', true)
  //   returns 2: true // gives true because does not do strict checking
  //   example 3: function SomeClass () {}
  //   example 3: SomeClass.prototype.someMethod = function (){}
  //   example 3: var testObj = new SomeClass()
  //   example 3: is_callable([testObj, 'someMethod'], true, 'myVar')
  //   example 3: var $result = myVar
  //   returns 3: 'SomeClass::someMethod'
  //   example 4: is_callable(function () {})
  //   returns 4: true
  //   example 5: is_callable(class MyClass {})
  //   returns 5: false

  const validJSFunctionNamePattern = /^[_$a-zA-Z\xA0-\uFFFF][_$a-zA-Z0-9\xA0-\uFFFF]*$/

  let name = ''
  let obj = null
  let method = ''
  let validFunctionName = false

  const getFuncName = function (fn) {
    const funcNameMatch = /\W*function\s+([\w$]+)\s*\(/.exec(String(fn))
    if (!funcNameMatch) {
      return '(Anonymous)'
    }
    return funcNameMatch[1] ?? '(Anonymous)'
  }

  if (mixedVar == null) {
    return false
  }

  if (/(^class|\(this,)/.test(String(mixedVar))) {
    return false
  }

  if (typeof mixedVar === 'string') {
    obj = getPhpGlobalScope()
    method = mixedVar
    name = mixedVar
    validFunctionName = !!name.match(validJSFunctionNamePattern)
  } else if (typeof mixedVar === 'function') {
    return true
  } else if (
    Array.isArray(mixedVar) &&
    mixedVar.length === 2 &&
    mixedVar[0] !== null &&
    typeof mixedVar[0] === 'object' &&
    typeof mixedVar[1] === 'string'
  ) {
    const receiver = toPhpArrayObject(mixedVar[0])
    obj = receiver
    method = mixedVar[1]
    name =
      (typeof receiver.constructor === 'function' ? getFuncName(receiver.constructor) : '(Anonymous)') + '::' + method
  }

  const callableCandidate = obj ? getPhpObjectEntry(obj, method) : undefined
  if (syntaxOnly || typeof callableCandidate === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  // validFunctionName avoids exploits
  // biome-ignore lint/security/noGlobalEval: needed for PHP port
  if (validFunctionName && typeof eval(method) === 'function') {
    if (callableName) {
      setPhpGlobalEntry(callableName, name)
    }
    return true
  }

  return false
}

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